When choosing a dot peen engraver for necklaces, consider the following factors:

l Mark Depth: The depth of the engraving should be sufficient to be visible, but not so deep that it damages the necklace. A shallow engraving is often preferred for delicate jewelry.

l Mark Size: The size of the font and design should be appropriate for the size of the necklace. Smaller necklaces may require smaller engravings.

l Mark Clarity: The engraver should produce clear and legible marks. This is especially important for small details and intricate designs.

l Material Compatibility: The engraver should be compatible with the material of the necklace, whether it's gold, silver, or another metal.

l Machine Precision: The machine should be precise enough to create accurate and consistent engravings.

l Ease of Use: A user-friendly interface can make the engraving process more efficient and less time-consuming.  

l Cost: Consider the initial cost of the machine, as well as the ongoing costs of maintenance and consumables.